System for generating oscillations



Aug, 17 1926.

S. LOEWE SYSTEM FOR GENERATING OSCILLATIONS Filed March 19.

Patent eale 18. 17.1926. i'

I UNITED. STATES smeuunn LOEWE, or BERLIN,

1,596,198 PATENT OFFICE.

GERMANY, ASSIGNOR T WESTERN ELECTRIC com- PANY, mooaronn'rnn, on NEWYORK, N. Y.,- A CORPORATION. or- NEW YORK.

' sYs'rnm non GENERATING OSGILLATIONS.

Application filed March 19, 1921, Serial '30. 453,841, and in GermanyApril 19, 1918, (GRANTED UNDER THE PROVISIONS 01 THE ACT OF MAIRCE 3,1921, 41 STAT. 13., 1313.)

This invention relates to oscillation-generators, using electrondischarge tubes hav-- ing a plurality of electrodes. An object L of theinvention is to provide .an oscilla- 5 tion generator, oscillatingdirectly into an antenna or other load circuit of variable impedance soarranged that variations of the antenna or load impedance have a verysmall effect on the frequency of oscillation. In other words theoscillation generator is s0 arranged that the frequency of the outputcurrent is substantially independent of said output current orvariations in the impedance of the output circuit. This is accomplishedby providing an anode, which constitutes the anode for an auxiliaryoscil lating circuit, but also functions as a grid with respect to aprincipal anode connected to the main oscillation circuit.

The invention also comprises novel electrode arrangements adapted to beutilized in tubes for carrying out the invention. From one aspect, thesystem herein described, may be regarded as an oscillation generatorconnected to an amplifier which amplifies the generated oscillations,the oscillation generator and the amplifier being combined in one vacuumtube and having a common cathode. The output circuit of the oscillationgenerator may be treated as the input circuit of the amplifier.

The generation of undamped electrical oscillations by vacuum tubesbecomes more diflicult in proportion as the antenna is more stronglydamped. At'the same time the total efliciency of the oscillationgeneration is greatly decreased. The present invention deals with anapparatus which will avoid this condition. The cause of this conditionwas recognized to be the comparatively ineflicient operation of the gridof the vacuum tube in the common arrangement. The basic idea of theinvention is the use of a means for increasing the grid effect beyondthat caused by the feed back.

\ Fig. 1 shows a space discharge oscillator embodying the invention.Fig. 2 represents a modified arrangement of the electrodes of I thespace discharge tube. Fig.3 shows an other arrangement of the spacedischarge tube electrodes. Fig. 4 shows a different form of oscillationgenerating. system embodying the invention.

In Fig. 1, a vacuum tube or space ourby the coil 9. The grid 3 isexcited by the auxiliary anode or output circuit 10 which may includethe resonant circuit 11 and thereby induce a potential upon the grid bymeans of the input circuit including'the coil 12. A part of the chiefanode battery may serve with advantage as the battery of the auxiliaryanode circuit, but the heating battery or a special source of voltagemay also be used for'this purpose. If the anode source Is not constant,but an alternating current machine, a transformer may be used, so thatthe voltage of the auxiliary anode circuit can even be chosen largerthan that of the chief anode circuit. 2

The method of operation is as follows:

Oscillations of the frequency determined by the resonant frequency ofthe tuned cir-' cult 11 are generated in the auxiliary anode circuit 10in the usual manner by means of the anode battery 6 and the feed back12.

Qn account of the arrangement of the osc llation generator with respectto the mam output circuit, the tuning of circuit 11 18 independent ofvariations in the impedance of the main output circuit. The gridvariations thus produced naturally act also on the real anode circuitconsisting of the anode 4, coil 9, and source of voltage 6; a highfrequency current flows in this circuit 90 and has the same period asthat of the auxiliary anode circuit. The antenna is now coupled with themain anode circuit and set in resonance with the frequency generated inthe auxiliary anode circuit. It is vital 95 that the auxiliary anodesystem andv the grid coil should be made as free from damping aspossible, since it is important be cause of the dissipation to generatethe highest possible grid variations with the least 100 possible energy.

The auxiliary anode system can always be chosen with a view to thegreatest possible grid effect, thatis with circuit 11 as free aspossible from damping and transforma- 105 .tion to high grid potential-Hence great It is advisable to arrange the auxiliary anode inside themain anode as shown 1n 'Fig. 2. The auxiliary-anode can itself beconstructed as a id and can act as such for the main anod d. (cf. Fig.3).

If the present method is combined with an ordinary circuit for thegeneration of oscillations, pure undamped oscillations W111 be obtainedwhen the main and auxiliary anode circuit are in resonance with eachother, and a beat transmitter will be obtained when the two circuits areslightly out of resonance.

The application of this is shown in Fig. 4.

A feed back with the antenna is formed by means of coil 13. If theantenna is slightly out of resonance with respect to circuit 11, beatsare obtained. I

\Vhat is claimed is:

1. Means for generating oscillations including a space current devicehaving electrodes,.an output circuit having a direct current conductiveconnection to electrodes of said device, and means including said devicefor transmitting oscillations to said output circuit from saidgenerating means at a frequency substantially independent of current insaid output circuit.

2. Means for generating oscillations including a space current devicehaving electrodes, an output circuit having a direct current conductiveconnection to electrodes of said device, and means including saiddevice, responsive to oscillations in said enerating means, fortransmitting said oscillations to said output circuit at a frequencysubstantially independent of current in said output circuit.

3. Means for generating oscillations in cluding a space current devicehaving a plurality of electrodes, and output circuit associated withsaid device, and means including a direct current conductive connectionbetween said circuit and one of said electrodes for transmittingoscillations to said output circuit at a frequency substantiallyindependent of current in said output circuit.

4. Means. for generating oscillations in cluding a space current devicehaving a plurality of electrodes, 3. variable load circuit directlyconnected to said device, and means including one of said electrodes fortrans-,

mitting oscillations to said output circuit at a frequency substantiallyindependent of variations in said load circuit.

5. Means for generating oscillations including a space current devicehaving a plu rality of electrodes, a load circuit containing a variableimpedance element directly connected to said device. and means includingone of said electrodes for transmitting oscillations to said loadcircuit at a frequency substantially independent of variations in saidimpedance element.

6. Means for generating voscillations ineluding a space current devicehaving a plurality of electrodes, a load circuit includingspacedischarge tube including a plurality of anodes and a common cathode,means for producing continuous discharges in a pinrality of space pathsbetween said cathode and said anodes; a control electrode adapted tocontrol the discharges in a plurality of said paths, associated reactivenetworks for producing self sustained oscillations in one space ath, anda work circuit connected to the ot er space path.

8. In an oscillation generator, a space discharge tube including acathode, control electrode and a plurality of anodes, means for causingsaid control electrode to vary the impedance of the space paths betweensaid cathode and both of said anodes, and an output circuit having adirect current conductive connection to an anode, whereby variations ofimpedance of said circuit are prevented from affecting the frequency ofoscillations.

9. In an oscillation generator, a space discharge tube including acathode, control electrode and a plurality of anodes, an oscillatorycircuit connected to said cathode and one anode, a load circuitconnected to said cathode and a second anode, said control electrodebeing adapted to independently control the spacevdischarge between saidcathode and said first mentioned anode, said first mentioned anode andsaid control electrode being adapted to jointly control the discharge tosaid second anode.

10. A space current device having an anode, cathode, and a controlelement, an

input circuit connected to said control element, and a tuned outputcircuit connecting said anode to said cathode to transmit current inresponse to oscillations in said input circuit, said input and outputcircuits being coupled together, a second anode for said cathode, and avariable output circuit connecting said cathode to said second anode totransmit current in response to oscillations in said first mentionedoutput circuit, the tuning of said first mentioned output cir cuit, thetuning of said first mentioned output circuit being substantiallyindependent of variations in said second output circuit.

11. A space current device having an anode, a cathode, and a controlelement, an input circuit connected to said control element, and anoutput circuit connecting said anode to said cathode to transmit currentin response to oscillations in said inputpircuit,

said input and output circuits being coupled together, a second anodefor said cathode, said second anode comprising portions located onopposite sides of said first anode, and a second output circuitconnecting said cathode to said second anode to transmit current inresponse to oscillations in said first mentioned output circuit.

12. In combination, a space current device, a load circuit including adamped antenna having direct current conductive connection to saiddevice, and means including said device for generating oscillationsunafi'ected by the damping of said antenna.

13. A circu it comprlsing a space discharge device, a cathode therein,two cold anodes therein, an external circuit connected to said cathodeand one of said anodes, a load circuit coupled to said external circuit,another external circuit connected to said cathode and the other of saidanodes, an

in ut circuitand a feed-back coupling from sald last named externalcircuit to said input circuit,,said first named external circuit beingfree of material external electromagnetic or electrostatic coupling tosaid input circuit.

14. A circuit comprising a space' discharge device having a cathode andtwo anodes, an input circuit, one of said anodes being included in anexternal circuit, means in said circuit to transfer waves to a loadcircuit, and the other of said anodes being included in another externalcircuit and means in said last named circuit functioning essentially totransfer waves to an input circuit of said device.

In witness whereof, I hereunto subscribe my name this ninth day ofFebruary, A. D., 1921. a

DR. SIEGMUND LOEWE.

